摘要
采用经典统计和地统计学的方法,定量分析了不同放牧强度(零放牧的对照、中度放牧和重度放牧)下贵州喀斯特人工草地植被的空间结构变化及其相关关系。结果表明,不同放牧强度下,草地植被表现为平均高度和盖度在零牧区表现优于中牧区与重牧区(P<0.05),丰富度指数、Shannon-Wiener指数随放牧强度增加而增加,地上生物量则随放牧强度增加而降低(P<0.01)。不同放牧强度下草地植被盖度和Shannon-Wiener指数的空间变异规律均能较好地拟合成指数模型,而草地丰富度的空间变异规律能较好地拟合成球状模型。放牧增加了草地的空间变异性:植被盖度、丰富度和Shannon-Wiener指数空间相关范围增加,植被高度和地上生物量的空间相关范围降低。不同放牧强度草地植被各特征变量均具有中等的空间相关性。不同放牧强度草地生产力与植物丰富度指数和多样性指数呈显著的负二次函数的单峰关系,其研究结果支持了中等生产力水平的草地物种多样性最高。
In order to ascertain the effect of livestock grazing on karst grassland, the characteristics of vegetation and the productivity, as well as the relationships between them, were quantitatively analyzed in this paper. Classical statistics and geostatistics methods were used to compare the performance on vegetation height, coverage, abundance, Shannon-Wiener index and aboveground biomass under different grazing intensity with sheep （none grazing, medium grazing and heavy grazing） . The results showed that, the average height and coverage of vegetation in none grazing area was significantly higher than that in medium and heavy grazing areas（p〈0.05） ; the richness index and Shannon-Wiener index increased as the grazing intensity increased, while the aboveground biomass decreased as grazing intensity increased. Analyzes on grassland vegetation spatial heterogeneity showed the spatial variation of vegetation coverage and Shannon-Wiener index under different grazing intensity can be well fitted with exponential model, while that of grassland richness can be well simulated with the spherical model. The base value of variation function showed that grazing increased the spatial variability of grassland. The relevant range（A0） of variation functions showed that grazing increased the relevant range of grassland vegetation coverage, abundance and Shannon-Wiener index, but reduced the spatial relevant range of the vegetation height and aboveground biomass. Spatial variation ratio analysis showed that the characteristic variables of grassland vegetation have medium spatial correlation under different grazing intensity. Significantly negative quadratic relationship was identified between grassland productivity and species richness index with a single unimodal distribution, and similarly in diversity index. These results support the theory that grassland with medium productivity has the highest biology diversity level.
出处
《草业与畜牧》
2015年第4期31-36,共6页
Pruataculture & Animal Husbandry
基金
贵州省体制改革项目(黔科合体Z字[2012]4005号)
贵州省农科院专项(黔农科院专项[2011]021号)资助
关键词
放牧
喀斯特草地
植被特征
空间变异性
Grazing
Karst grassland
Vegetation characteristics
Spatial variability
